Marine velocipedes having a pair of elongated floats supporting a propelling mechanism analogous to that employed by an ordinary bicycle construction for driving a propeller to move the velocipede on the body of water is shown by C. Clark in U.S. Pat. No. 637,547. The velocipede has a pedal operated drive train which rotates the propeller through shafts connected with a universal joint. K. R. Foredtret in U.S. Pat. No. 1,761,883 discloses a water vehicle having a pair of elongated pontoons supporting a bicycle-type frame. A pedal drive operates to rotate a propeller to move the vehicle on a body of water. Handlebars rotatably mounted on the frame are used to move a forwardly located rudder to steer the vehicle. Additional developments in human powered vehicles are shown by G. W. Mattson in U.S. Pat. No. 2,177,074 and J. J. Zimmermann in U.S. Pat. No. 3,352,276.